>>16765941http://pokemonshowdown.com/Go here, make an account, make a team, get your ass kicked. This website will let you freely tinker around with pokemon and builds without having to go through the grueling process of breeding, so when the time comes you know that the pokes you're making are a quality team.
Research smogon. They know what they're talking about, even if this board hates them. Don't blindly copy/paste their sets though, especially since all of it is a generation old now and may no longer be as relevant. It's still good to get a feel for how the pokemon works in a competitive sense.
Lastly, and this is just a recommendation, always make sure your team has a pokemon that you like on it. Unless you're playing super hard competitively, using a cookie-cutter team will likely feel hollow. I recommend starting from there, actually. Pick one pokemon that you like and make a team around it (just make sure the pokemon you're choosing actually has a hope of competing).